L10n report: December 2021 edition (2021 wrap-up)

Hello localizers,

You can find the latest edition of the l10n report here: https://mzl.la/3yzZ7Es.

Since this is also the last edition of the year, you will find a few numbers and accomplishments of the community for the whole 2021.

Thanks for the amazing work that you did over this complicated year to support Mozilla and your languages.